The effect of solutes on the formation of zinc complexes of chlorophyll derivatives in processed green vegetables was studied using a pea puree model system containing added Zn2+ and heated at 121 °C for 30 min. Divalent cations decreased the pH of unheated purees and zinc complex formation after heating, suggesting that the pH-lowering effect of divalent cations may influence complex formation during heating. Malate, tartrate, citrate, phosphate, and EDTA anions decreased zinc complex formation because of their ability to chelate Zn2+. Thiocyanate, benzoate, oleate, and caprylate anions increased complex formation, while sucrose, glucose, and fructose had no effect on the reaction. Zinc complex formation increased when sodium dodecyl sulfate detergent was added but decreased in the presence of Tween 80, cetyltrimethylammonium bromide, and Triton X-100. The results suggest that surface active anionic compounds facilitate zinc complex formation by adsorbing onto chloroplast membranes and increasing the negative surface charge.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)